1. Field of the Invention
The present invention relates to an image scnsor or an image sensing apparatus with less noise.
2. Description of the Prior Art
Various kinds of image sensors have been conventionally considered as shown in the Official Gazette of Japanese patent application publication Laid-Open No. 32595/1975.
FIG. 1 is a diagram showing an example of such a sensor.
In the diagram, a reference numeral 1 denotes a photo detecting unit; 2 is a memory unit; 3 a horizontal shift register; 4 an output amplifier; and 5 a photo receiving window corresponding to the window provided in a package of a CCD.
In such a sensor, an optical image entered the photo detecting unit 1 through the window 5 is converted to distribution information of charges. The charge information formed in the photo detecting unit is read out for every horizontal line through the horizontal shift register 3 and output amplifier 3 for a predetermined interval.
Charges are also formed in a semiconductor substrate around the photo detecting unit 1 due to the photo receiving window 5 and these charges leak into the photo detecting unit 1. Thus, there is a drawback such that the noise is easily added to the video signal responsive to the right and left side end portions of the photo detecting unit 1 in the diagram.
In addition, there is another drawback such that thermions are formed even near the memory unit 2 and these thermions leak therein.